In the minutes before a turboprop plane plunged to the earth killing all 49 people aboard and one person on the ground, the pilot and crew were recorded discussing "significant ice buildup" on the plane's windshield and the leading edge of the wings, federal investigators said today.

The black boxes recovered from the burning remains of Continental Express Flight 3407 also indicated that the de-icing button in the cockpit had been in the "on" position.

Shortly after that conversation, Capt. Marvin Renslow deployed the plane's landing gear and wing flaps to slow down the plane in preparation for landing.

"Severe pitch and roll [began] within seconds" of the flaps being deployed," said Steven Chealander, spokesman for the National Transportation Safety Board. Chealander said that means the plane's nose bucked up and down while the wings dipped and rose violently.

The plane plummeted to the earth so rapidly that Renslow and his crew never had time to radio a mayday alert.

Witnesses say the Dash 8 Q400 Bombardier aircraft came down in such a steep fall that it demolished the house, but spared other homes in the crowded neighborhood.

Miraculously two women, Karen Wielinski, 57, and her daughter Jill, 22, escaped the home in the town of Clarence Center, N.Y., with minor injuries. The Buffalo News reports that Douglas Wielinski, 61, is also registered as living at that house, but there was no official identity of the victim.

Karen Wielinski told WBEN radio that she was in a first floor family room at the rear of the house and her daughter was in an upstairs room at the front of the house.

Karen Wielinski said she was immediately buried under debris and thought she was going to die until she noticed "a little light on the right of me... I shoved off whatever was on me and crawled out the hole."

"I didn't think I was going to get out of there... that little bit of light gave me hope," she said.

When she emerged from the debris "the back of the house was gone, the fire had started, I could see the wing of the plane and I could see Jill off to the side crying, hysterical," she said.

Wielinski, who suffered a fractured collar bone, said Jill Wielinski had been trapped by fire, but managed to get out somehow in her stocking feet without any injuries. She was later treated for scratches she suffered while running away from the wreckage.

"I grabbed her and ran to the back of the yard" and went to neighbors for help, she said.

Her husband, Doug, was in another room in the middle of the house, Wielinski said. "The plane came down in the middle of the house. Unfortunately, that's where Doug was," she said and began to cry.

The crash occurred in light snow about 10:20 p.m. Thursday as the turboprop was about five miles away from Buffalo Niagara International Airport. The 74-seat plane was flying from Newark Liberty International Airport in New Jersey.

It was the first fatal crash of a commercial airliner in the United States in 2½ years.

President Obama voiced condolences, saying "our hearts go out to the families and friends who lost loved ones."

The crash site erupted into a massive fire, fed by 5,000 pounds of fuel the plane was carrying as well as a natural gas leak within the demolished building.

Brendan Biddlecom, who lives a few blocks from the crash site, told "Good Morning America" today that he had just finished putting his children to bed.